To make various industrial products and the like have constant quality, for example, the products are maintained to have the same color on surfaces thereof. For this purpose, at any stage from the manufacture to the shipment, the color of the surface is measured with a colorimeter or the like to manage the color of the surface. Such a colorimeter includes, for example, an illumination light reception unit including a light source that illuminates a surface of an object whose color is to be measured, such as a product (also referred to as a color measurement object), and a sensor that receives light such as reflection light generated from the surface.
Incidentally, in regard to a part of the surface of the color measurement object whose color is to be managed, that is, a part whose color is to be measured (also referred to as color measurement part), the size and shape may vary depending on various conditions including the shape and size of the color measurement object, the request from clients, the manufacturing method, and the like. However, preparing a different colorimeter for each condition is a large burden on a manufacturer economically.
In view of the above, a portable color measurement device has been suggested (for example, Patent Literature 1) which includes an exchangeable nose cone disposed between a color measurement object and a main body of a colorimeter in accordance with a condition. In this device, for example, the size of a region whose color is to be measured (also referred to as color measurement region) can be changed. This nose cone includes a window part that defines the size of the color measurement region and the like, and is attached to a colorimeter so as to cover the illumination light reception unit, and can function as a member (also referred to as mask member) to be in contact with the color measurement object when the color of the color measurement object is measured.
In such a structure, when the mask member is exchanged, it may be necessary to change an optical system and a calibration coefficient or the like used in the calculation at the color measurement in accordance with the kind of the mask member. In view of this, the device disclosed in Patent Literature 1 includes one or more magnetic switches on a lower half of the main body. The magnetic switch monitors a magnetic field generated from a magnet disposed on the mask member. Thus, the kind of the mask member is automatically recognized and displayed.